1. Field of the Invention
The present invention relates to a driving device and a method for controlling the same.
2. Description of the Related Art
Ultrasonic operation apparatuses are known as one of apparatuses capable of performing treatment on a living tissue, such as incision, hemostasis, and coagulation. Ultrasonic operation apparatuses generally include an ultrasonic transducer, a driving device, and a probe. The ultrasonic transducer includes a piezoelectric element such as a piezoelectric device. The driving device supplies the ultrasonic transducer with driving power to cause the ultrasonic transducer to perform ultrasonic vibration. The probe transmits the ultrasonic vibration generated in the ultrasonic transducer to the distal end portion of the ultrasonic operation apparatus. In the ultrasonic operation apparatus as described above, constant current control is performed to maintain a constant current supplied from the driving device to the ultrasonic transducer such that vibration of stable amplitude is performed in the probe, even when load on the ultrasonic transducer fluctuates. For example, the ultrasonic operation apparatus presented in Japanese Patent Application KOKAI Publication No. 11-70118 performs control to fix a current supplied from the driving device to the ultrasonic transducer, by determining impedance in driving of the ultrasonic transducer, which corresponds to mechanical load on the probe, and feeding back the impedance to the driving device.